The invention relates to a method of making conference call connections in computer-controlled telephone exchanges which combines the voice signals of the conference participants on a digital basis, forms a signal of the total of the speaking levels of a certain number of the most active participants as well as distributes it in an undamped manner, and suppresses the voice signals of the inactive participants.
In computer-controlled telephone exchanges which provide connections for telephone conferences, it is known to store a user authorization as well as to monitor the number of the connected parties and to control them by means of different memories, in such a way that, for example, a maximum number of four parties is simultaneously connected, as disclosed in German Published, Non-Prosecuted Application DE-OS No. 32 06 830.
In order to permit a larger group of people, who may also be subscribers in various local exchanges within or outside of the country, to participate in a conference, a method was proposed which assigns groups of conference callers to public exchanges, as described in German Pat. DE-PS No. 35 15 646. The voice channels are switched on or off by a program in the associated group processor in which a suitable pattern for a conference call connection with the ariving levels for each conference port is stored. A check and new level determination is performed with each new level message. As a result it may be necessary to limit the flow of data from the group processor in order to preserve the computing capacity thereof for the control functions.